Underreamer



Patented Sept. 29, 1925.

JOI-IN GRANT, OF LOS ANGELES, AND STEWART L. CAIVIPBELL, QIE BERKELEY, CIT-.Ll-

PATEarr FORNIA; SAD CAMPBELL lFfJSiSGrllTOP, TO SAID GRANT.

UNDERREAM ER.

Application filed January 26, 1925. Serial No. 4349.

To all whom t may concern.'

Be it known that we, JOHN GRANT, a citizen of the United States, and resident of Los Angeles, in the county of Los Angeles, State of California, and STEWART L. CarirnnLL, a citizen of the United States, and resident of Berkeley, county of Alameda, State of California, have invented new and useful improvements in Unde-rreamers, of which the following is a specification.

This invention relates to a rotary underreamer, such as may be used in hydraulic rotary drilling of wells. ln drilling wells with -rotary drilling rigs, it is the common practice to introduce casing into the hole and follow the drill bit with the casing as hole is made. vVith the casing in position, if it is desired to ream the hole, it is necessary to have a collapsible underreamer in order that it may be introduced through the casing to the lower end thereof. matically collapsed upon withdrawal into the casing so that it may pass therethrough. Such tools must be simple in structure, durable, withstand great strain, have long life, and be easily manipulated.

These objects together with other objects and corresponding accomplishments will be apparentduring the course of the following description. In the accompanying drawing forming a part of this specification, an embodiment of our invention is illustrated. ln the drawing:

Fig. 1 is an axial sectional view through my improved underreamer; Fig. 2 is an elevation of the same as seen looking in the direction of the arrows 2 of Fig. 1; Fig. 3 is a sect-ion as seen on the line 3 3 of Fig. 1; Fig. 1 is a fragmentary sectional View showing a roller type of cutter; and Fig. 5 is a section as seen on the line 5-5 of Fig. 4.

Referring more particularly to the drawing, the numeral 6 indicates the body or stock of the reamer, it is provided at the upper end with a tapered threaded pin 7 adapting it to be connected to a string of drill pipe. The lower end of the body has a threaded tapered boX indicated by 8, adapting the tool for connection to a drill bit or other tool in advance of the underreamer. Extending longitudinally of the body is a recess 9 having its inner face slant- Such an underreamer should be auto-y ing so as to form a slot open to the other side of the body as indicated by 10. tending across the recess adjacent the upper end thereof is a pivot pin 11 ha\ A erating finger 12 mounted thereon. A pin 14 has mounted thereon a spring finger 15 tending to maintain the pin in its outer position. upon a pin 17 within slot 1t). The cutter is provided with blades 18 and 19 which are diametrically opposite one another'and arranged so that the cutters may be turned to dispose-both blades within the boundary of the body. rlhe cutter is provided with a notch 20 and within which the tip of linger 12 is disposed. rlhe parts are so arranged that upon pressing linger 12 inwardly, the tip thereof will force the lug on the cutter inwardly and cause the cutter to be turned so that blades 18 and 1S) are within the body and in collapsed position. Fressure upon knuckle 13 to force the linger l2 inwardly will cause collapse of the cutter. Extending through the body is a water passage 21 for circulation fluid, the passage being offset in the body to pass around the recess 9 and slot 1t). However, the water passage may be disposed in any convenient manner.

rlhe tool is collapsed by pressing inwardly upon the knuckle 13 so as to swing 'the blades 18 and 19 within the body. rlhe tool is then inserted in the casing, the wall thereof maintaining the finger 12 in its inner position, the blades being retracted within the body so that the tool may be lowered. As soon as the tool passes out of the casing, spring 15 presses finger 12 outwardly, the tip of the linger pressing against the blade 18 and swingingthe cutter into the position shown in Fig. 1. The underreamer is now expanded and ready for work. 'llo withdraw the underreamer, it is pulled upwardly, the knuckle 13 engaging the lower end of the casing or shoe and being forced inwardly as the body is drawn into the casing.

In Figs. et and 5, similar parts of a modilied form of the tool are indicated by the same numbers as used for Figs. 1, 2, and 3, but with a prime added. The cutter 16 has arms 22 and 23 upon which are journalled roller cutters 24: and 25. The action of the several parts in expanding and contracting is the same as in the construction before dei cutter 1G is pivotally mountedscribed. The recesses 9 and l0 must be cut to accommodate the passage of the cutter rollers.

What we claim is:

l. An underreamer comprising a body, a cutter pivotally secured thereto, said cutter being provided with cutter arms which when in working position project beyond said body on opposite sides thereof and in non-working position are disposed within said body, means on said body inwardly movable by engagement with a well easing, said means being connected to said cutter so that upon inward niovement of said means the cutter arms will be swung to innermost position.

2. An underreamer comprising a body, a cutter pivotally secured thereto, said cutter being provided with cutter arms which when in working position project beyond said body on opposite sides thereof and in non-working position are disposed within said body, a finger pivotally mounted on said body and arranged to be moved inwardly by engagement with a well casing, said finger' being connected with said cutter so that upon inward movement of said iinger the cutter arms will be swung to innermost position thereby and upon outward movement of said finger the cutter arms will be swung to projected position.

3. An underreamer comprising a body having a slot extending transversely therethrough, a cutter having diametrically opposite arms pivotally secured to said body and disposed in said slot so that said cutter may be turned to dispose said arms within said body or turned to dispose said arms so that they project laterally therefrom in working position, and a finger mounted on said body and connected to said cutter so as to turn the latter, said linger tending to project beyond said body so as to maintain said cutter in projected position and when said linger is in innermost position said cutter is within said body.

4L. An underreamer comprising a body having a slot extending transversely therethrough, a cutter having diametrically opposite arms pivotally secured to said body and disposed in said recess so that said cutter may be turned to dispose said arms within said body or turned to ,dispose said arms so that they project laterally therefrom in working position, a linger mounted on said body and connected to said cutter so as to turn the latter, said finger and cutter' being arranged such that said finger tends to project beyond said body when said cutter is in projected position and when said finger is in innermost position said cutter is within said body, and means urging said cutter into working position.

5. An underreamer comprising a body having a slot extending transversely therethrough, a cutter provided with a cutter arm pivot-ally secured in said body and disposed in said slot so that said arm may be disposed in position such that the arm is within the body or may he disposed in a position such that the. arm projects laterally therefrom in working position, a iinger pivotally secured to said body and disposed in said slot, said finger having an abutment faced outwardly, said cutter and said finger being engaged so that when the abutment extends beyond said body the cutter extends beyond the body and when the abutment is disposed within said body, said Cutter arm is retracted within said body, and resilient means tending to urge the cutter arm outwardly.

6. An underreamer comprising a body having a recess extending transversely therethrough, a cutter provided with a cutter arm pivotally mounted in said body and disposed in said recess so that said arm may be disposed in a position such that the arm is within the body or may be disposed in position such that the arm is projected laterally therefrom in working position, a tinger pivotally mounted in said body and disposed in said recess, the finger having au abutment facing outwardly, said cutter being provided with a notch, the tip of Ysaid finger resting in said notch whereby to engage the cutter so that when the abutment is moved outwardly beyond the body the cutter is moved thereby beyond the body and when the abutment is moved within the body the cutter arm is retracted thereby within said body, and resilient means tending to urge the cutter arm outwardly.

In witness that we claim the foregoing I have hereunto subscribed' my name this 20th day of January, 1925,

JOHN GRANT. Y In witness that we claim the foregoing I have hereunto subscribed my name this 16th day of January, 1925.

STEWART L. CAMPBELL. 

